Will the Bhoys hold off Bharcelona's superstars or will they end the evening in a hhot fhunk? All I'm going to say is this: Gary Caldwell. Make your own mind up. (Celtic fans will thank me for this if the line I took on Dirk Kuyt last night is anything to go by.) Anyway, here are the teams:

Meanwhile Thierry Henry gets the chance play well in a big game for the first time in his entire career. Go on, Thierry! You can do it! Valdes, Puyol, Milito, Marquez, Abidal, Iniesta, Toure Yaya, Deco, Messi, Henry, Ronaldinho. Subs: Pinto, Xavi, Gudjohnsen, Eto'o, Sylvinho, Giovanni, Thuram.

Referee: Peter Frojdfeldt (Sweden)

You'll Never Walk Alone, If You Know Your History It's Enough To Make Your Heart Go Aaaaaarrrrgggggnnnnnnnnfffffff, etc., and so on, and so forth. Yep, Parkhead is reverberating to a medley of traditional Celtic songs. One of them sounds suspiciously like Brian & Michael's 1978 paean to LS Lowry, Matchstalk Men and Matchstalk Cats and Dogs. That can't be right, surely?

And we're off! Parkhead is pounding. One minute and 17 seconds elapse before Celtic get a chance to touch the ball. Then Ronaldinho crosses from the left to Messi, who lets the ball run under his foot for a goal kick. Fifteen seconds or so later, Boruc puts his foot through it.

2 min: A nervy start for Celtic: first Henry is allowed to skitter free down the left, but his cross is too deep; then McGeady gives the ball away in midfield to Ronaldinho, but the Brazilian's ball forward towards Messi is way too strong.

5 min: This is all Barca. Ronaldinho cuts inside from the left - they've obviously decided to attempt to target and/or isolate Caddis - and slips a ball into the box towards Henry. Any flick would surely have wrongfooted the advancing Boruc and resulted in the fanciest of goals - think that goal Wayne Rooney got against Reading the other week - but Henry can't connect and Celtic are safe.

9 min: McGeady and Nakamura both attempt to swing balls into the Barca box from varied positions on the pitch, but both attempts are easily charged down. A couple of minutes of possession, if not pressure, which gives the home crowd something to sing about.

12 min: What a save from Boruc: Celtic fanny around in the box and give the ball away to Henry, who cuts it back from the byline to the right of goal for Iniesta, who sees his powerful drive parried clear. And then another brilliant save, as the ball comes straight back to Henry, whose effort is once again parried clear.

13 min: Celtic are rocking here - now Boruc nearly fists a corner into his own net, but the ball bounces kindly and is hacked clear by Caddis. At the moment it looks like a matter of when, not if.

15 min: WHAT A GOAL AGAINST THE RUN OF PLAY!!! Celtic 1 - 0 Barcelona! McGeady skins Puyol down the left and feeds McDonald, who falls over in the box over his own feet but manages to get back up and slip the ball out to Naylor, who swings in a totally undefendable (that's not a word, is it) outswinging cross to Vennegoor of Hesselink, who simply can't do anything but power a header straight past Valdes from the edge of the six-yard box. What an utterly outstanding cross!

17 min: FROM HERO TO ZERO IN TWO MINUTES 22 SECONDS. Celtic 1 - 1 Barcelona. Naylor is caught floundering as Messi exchanges passes with Deco on the right-hand edge of the area and lifts the return past Boruc into the top left of goal. What a fantastic crisp move; actually it's pretty hard to criticise Naylor for that, it wasn't as though he could do much about it.

19 min: Champions League debutant Robson goes in the book for upending Messi. This match is pelting along at one hell of a pace, which is good, but for purely selfish purposes BAH.

22 min: This is all Barca again. Hartley pulls Marquez back just outside the area; free kick. The ball is totally central, 25 yards out. Ronaldinho's effort to get the ball up over the wall and down into the top left corner is decent - Boruc would never have got there - but too high. This is a cracking game.

25 min: Jesus, have 25 minutes gone already?

26 min: Ronaldinho slips the ball ahead to Abidal down the left; the full-back's cross is easily cut out by Boruc but Caddis is having a hellish time here.

27 min: Caldwell gets away with the most blatant handball I've seen for a while. It's only on the touchline, no need for tears and grief, but Deco slips into a bubbling stew and catches the ball himself in protest. That's a free kick to Celtic, sir.

30 min: Deco was lucky to escape a caution a couple of minutes ago, but he's booked now for stopping Hartley taking a quick free kick. Parkhead is quick to cheer the decision, given Deco spent over 77 minutes of the 2003 Uefa Cup final on the turf, snaking around the feet of Celtic players as Porto Mourinhoed their way to a 3-2 win.

33 min: Magnificent play from Yaya Toure there, who sashays down the centre of the park, exchanging one-twos hither and yon, eventually feeding Ronaldinho down the left. Ron powers into the box and escapes a lunge from Caldwell - he could easily have gone over an outstretched leg Michael Owen style there - before whipping a cross into the six-yard box which is well cleared by McManus.

36 min: Abidal shrugs Nakamura off the ball on the left wing, bombs forward and whips the ball into the box for Henry, who cuts in from the right and blasts over the bar from eight yards. This is again beginning to look a matter of when not if for Barca, but then remember what happened the last time I said that.

37 min: YOU ARE NOT GOING TO BELIEVE THIS. Celtic 2 - 1 Barcelona! McGeady shifts the ball inside from the left wing past Puyol and Iniesta and dinks a ball towards the penalty spot where Robson awaits - and flicks a header over the leaden Valdes and into the net! OK, let's see what happens if I say: this is beginning to look a matter of when not if for Barca. It can't work three times, surely?

41 min: Nakamura swings in a corner from the left with Vennegoor of Hesselink who... can't get to the ball as Valdes claims. Oh well, three in a row was too much to ask for. Barcelona look stunned, though.

43 min: McGeady is all over Puyol. He diddles him again down the left, cuts inside and hammers a shot towards the top right... though it sails too high. CLOWNS IN SFA BLAZERS CAUSE PUNTER TO CLAMBER ON SOAPBOX DEPT.: "Frankly I think the incompetence of the SFA in allowing Scotland's Aiden McGeady to slip through their greasy fingers and into the Republic's arms should be made more of," writes Al Loch. Preach on, brother. "He wasn't born there, nor were his parents, but due to the SFA's pernickitiness (sic) of not allowing kids who don't represent their schools to represent their country at that level they missed out on one of the best young talents to emerge in our skill-starved little corner of Europe. I certainly don't begrudge him playing for his grandfather's country but it's a subject that surely deserves a little more investigation into how they managed to piss him off that much. Goodness knows Scotland could do with his, albeit rather unpredictable, talents."

And so ends a brilliant half of football: Celtic 2 - 1 Barcelona. Ronaldinho nearly breaks clear in the Celtic box but Boruc does well to come out and smother at his feet. He takes a whack upside his head for his trouble, so will be thankful that the clumping of boot on skull is drowned out by the referee's half-time whistle and the frenzied cheers of the crowd, who thankfully haven't sung that Brian & Michael rip-off again all half.

International relations the Website Formerly Known As Guardian Unlimited Sport way: "With all love and due respect," hisses Juan Arcas, "if you EVER AGAIN type the sequence 'when not if' on your keyboard, the invincible armada and a few friends from Barcelona will pay you a visit." Well, I'm far too much of a coward to do anything but kowtow to your wishes, Juan, so no problem. Unless any travelling troupe of louts fancy swinging round via the Irish Sea and heading Arcas and his goons off at the pass, in which case I'll keep whenning and iffing like billy-o.

And we're off again! No changes at half time. "Don't worry about Juan Arcas," says the soothing voice of Ephraim Gadsby. "It would take so long to find the invincible armada and raise it from the seabed that you'll have plenty of time to make your escape."

46 min: Puyol manages to successfully tackle McGeady! Yes, he really has done it! "Not to burst your bubble," says Donal M. O'Brien, hoving into view with a grin and a pin, "but McGeady's declaration for Ireland had more to do with his own personal disposition towards Ireland than any mistakes by the SFA. Of course, one can just ignore McGeady's own comments on the matter or the various videos of him as a young lad wearing an Ireland jersey. Details, details." Oh. Can't we blame the SFA blazers anyway? It's much more cathartic that way.

49 min: Messi juggles the ball on the edge of the Celtic area. Iniesta and Deco combine brilliantly down the right to nearly free Henry. Messi has a poke from outside the box which is deflected wide. Corner. From which Iniesta nearly finds the top left corner. It's only a matter of etc, and so on, and so forth.

51 min: A dodgy header back towards Boruc by McManus nearly allows Henry the chance of a shot, but Caldwell does well to lumber between the ball and the Barca striker and the danger is over.

51 min and a bit: SUCH A BRILLIANT GOAL!!! Celtic 2 - 2 Barcelona. This time it really was a matter of when, not if. Caldwell gives the ball away - and it soon finds the feet of Henry, who scores a wonderful goal, picking it up in the inside left channel, sailing into the box, and curling a majestic shot into the top right corner. He never does it in the big games? Who said that? And does this mean Arcas will call the warships off? Please call the warships off.

54 min: Celtic make a change. Vennegoor of Hesselink is replaced by Georgios Samaras.

55 min: They're definitely picking on poor Paul Caddis; now Ronaldinho pelts down the left, drops a shoulder and has a dig. It's no good, though, low and hard but well left of goal.

57 min: What a move from Barcelona: Deco sweeps the ball left to right to Messi, who cuts inside, one-twos with Henry, and nearly breaks clear in the box. Naylor does fantastically well to extend a leg and poke the ball clear of danger. Barcelona are looking very dangerous at the moment.

60 min: Hartley is booked for a nibble on Iniesta. The struggling-but-who-can-blame-him Caddis is replaced by Mark Wilson. Meanwhile David Reid is not letting the McGeady thing lie. "Yeah, well I wore a Brazil shirt when I was kid, doesn't make me part of the gang." In my official capacity as coward, I'm staying out of this.

61 min: Messi cuts inside from the right and belabours a shot straight into Boruc's midriff. When, if, not: arrange as you see fit. With this in mind, Adam Keeling writes: "Can you type 'It's a matter of when not if Adam Keeling misses out on the 270 million dollar Mega Millions jackpot' into your MBM? I'll share the winnings with you. I promise." It's a matter of when not if Scott Murray misses out on the 270 million dollar Mega Millions jackpot.

63 min: Abidal bowls down the left and has a dig which Henry nearly reroutes past Boruc into the bottom left corner. It's just wide. Here, what's Mega Millions?

64 min: Nakamura tries to find the head of Robson in the Barca box with a long free kick, but there's nothing doing and the danger is easily cleared. Meanwhile Celtic manager Gordon Strachan takes his last roll of the dice - I mean, he's not going to make any tactical changes from the touchline, is he - replacing Hartley with Donati.

65 min: To a chorus of boos, Deco is replaced by Xavi. "Why do the Celtic fans feels aggrieved with Porto over the 2003 Uefa Cup victory?" asks Luis Correia. "Porto were the better team. Celtic were kicking the Porto players more than the ball in that game. Their fans make some exceptional whine from their sour grapes. FORCA PORTO." In my official capacity as coward, I'm etc, and so on, and so forth.

67 min: Celtic have their first shot in anger of the half, Donati sending a daisycutter towards the bottom right of Valdes's goal; it's parried clear with some ease, though.

69 min: Henry pelts down the left but is bustled out of it at the last by Caldwell. That's a corner, from which nothing comes.

71 min: Henry is well up for this. He rolls a precision ball across the face of goal from the left towards Ronaldinho, unmarked in the centre six yards from goal; McManus does well to shank clear. Then Iniesta tests Boruc from the corner; that's a safe pair of hands from the keeper. This is a matter of... yeah.

72 min: Ronaldinho is off to a nearby nightclub; Eto'o comes on to replace. I mean, that's not really fair, is it.

73 min: The first thing Eto'o does is allow himself to be tossed into the air like an old sock by Naylor. That's a free kick, nearly 30 yards out but quite central. And how Celtic get away with what happens next: Iniesta swings in a ball which finds the head of Puyol, six yards out and all alone. He must score - but somehow heads straight at Boruc, who snaffles the ball with relief. A great free kick from an attacking point of view, but terrible defending: where were the Celtic back four?

75 min: Robson nearly gets his head onto a Donati up and under, but Valdes is quick to claim.

78 min: WHAT A COCK-UP AT THE BACK: Celtic 2 - 3 Barcelona. Eto'o cuts inside from the right. His effort to free Messi in the box is cleared by Caldwell but the ball hits Donati and comes straight back to Messi, clear in the area. He shifts the ball left, leaving Caldwell for dead, and slips the ball tidily into the bottom left. Brilliant skill from Messi, but oh dear.

82 min: Eto'o nearly breaks into the Celtic box but is stymied by the head of McManus, who bundles the ball into touch. This is looking ominous for Celtic; it's going to be difficult enough in the Nou Camp as it stands, but another goal for Barca here will surely be curtains. "I don't recall Celtic players having much opportunity to kick the Porto players in the 2003 Uefa Cup final," writes Don Watson. "The minute anyone moved in their direction they hurled themselves dramatically to the turf." "Forka Porto indeed!" adds the slightly less subtle James Sprague.

84 min: That was nearly it for Celtic: Henry races straight down the middle, lays off to Eto'o and nearly latches onto a superb reverse pass. Boruc does well to clear the danger.

85 min: What a save from Boruc! Xavi releases Puyol into acres down the right. The ball's rolled across the face of goal towards Henry, who opens out his body and sidefoots towards goal... only for the Celtic keeper to smother wonderfully. Celtic are all over the shop here.

87 min: Good work from Abidal down the left, then Henry, clear in the area, slips the ball past Boruc and into the bottom corner. Luckily for the home side, the only reason he's clear in the area is because he's a couple of yards offside. Henry shrugs his shoulders and then buggers off, to be replaced by Eidur Gudjohnsen.

89 min: McGeady is cracked on the shin by a disgraceful studs-up rake from Puyol. Can't say for sure if it was intentional, so benefit of the doubt and all that. Plus the injured player himself isn't really complaining. Forget I said anything. There will be four minutes of added time.

90 min +2: From the left wing, Samaras slips a fast ball to McDonald's feet in the Barca area. The striker slips, there's a half-hearted shout for a penalty... but nobody's heart's really in it.

Full time: Celtic 2 - 3 Barcelona. Samaras is booked for diving in the Barca area with Puyol running not-so-closely behind him... and that's that. Barcelona were stunning in that second half, though it has to be said that despite all the pressure from the Catalan side, Celtic were the architects of their own downfall. Despite an amazing performance in the first half; they'll really need to go some to score at least two goals to win the tie at the Nou Camp. Especially as they haven't won away in the Champions League for God knows how many centuries. Nighty night.